As in Nelly's "I'm from the Loop and I'm proud" is a reference to the Delmar Loop in University City (U City), in Saint Louis County, MO. The Loop (and much of U City) is an area that mixes college students with low income housing and edgy shops/restaurants/etc. Several (formerly) main thoroughfares in the St. Louis area run in a rough semicircle around the city, hence the Loop.